Sea forts of the Thames Estuary

The architecture of the Second World War has led to some particularly unusual structures across the British Isles, from dragon’s teeth anti-tank blocks to cunningly hidden pillboxes. Most of us will have come across these at some stage in our wanders (hardly surprising as around 18,000 pillboxes alone were constructed during the war). However, less well known is the existence of some stranger sights from wartime lurking in the Thames Estuary, collectively known as the Maunsell Forts.

Grey skies over Red Sands

These offshore Forts were constructed in the 1940s to help protect the intensive sea traffic into the Port of London, which had been threatened by magnetic mines dropped by enemy aircraft. Over one hundred ships sank in the first few months of the war, preventing vital supplies from reaching Britain. The anti-aircraft batteries installed on the Maunsell Forts were intended to counteract this threat and successfully shot down 22 planes during the war.

Two different designs of forts were constructed in the Thames Estuary and can still be seen to this day. The earliest forts (known as the Naval Forts) consisted of gun platforms constructed on two 60 foot columns, whilst the later design (known as the Army Forts) consisted of seven interconnected towers.

I have long wanted to see the forts for myself and the chance discovery that the world’s last sea going paddle steamer (PS Waverley) would be making an excursion to the forts seemed too good an opportunity to pass up. Our trip took us from the Town Pier at Gravesend to the Thames Estuary, with a short stop at Southend Pier on the way – a total of six hours on the water.

PS Waverley approaches Gravesend Town Pier

On the way out to the forts we had plenty to look out, from easily overlooked sights (such as the World War Two radar tower near Tilbury cleverly disguised as a water tower) to sights too large to miss (such as the new London Gateway deep water port with 138m high cranes that were shipped ready-built all the way from China).

After leaving Southend Pier we sailed past a stranded section of the Mulberry Harbour that never made it to Normandy after springing a leak whilst en route from the Humber in 1944. The 2,500 ton concrete Phoenix caisson was towed in to the Thames Estuary for inspection but broke free from its mooring and has been stranded on the sandbank off Thorpe Bay, damaged beyond repair, ever since. The masts of another wreck from that year, the SS Richard Montgomery, were just about visible along with the warning buoys that mark out the exclusion zone (she still carries a lethal cargo of 1,400 tonnes of wartime munitions).

Light and shade

The landscape was a striking mixture of desolate flat land that can barely have changed over the centuries, new developments (such as the extensive wind turbines of the Kentish Flats Offshore Wind Farm) and industrial sights that are soon to disappear (including long closed oil refineries and distant power station chimneys that are scheduled for demolition). The darkening skies gave all this a rather atmospheric, gloomy quality – even if it was a bit rubbish for photography!

In the distance we could now see the seven towers of the sea fort at Red Sands, which were constructed between July and September 1943. Red Sands is the most complete of the three army forts constructed during wartime. The first of the forts, on the Nore Sands, was dismantled in the 1950s after proving to be a hazard to shipping whilst one of the towers at Shivering Sands was demolished after a collision in 1963. It’s not hard to see why these strange structures were picked as an outdoor location for Doctor Who in the 1960s (Red Sands stood in for an offshore oil refinery threatened by deadly seaweed monsters in the story ‘Fury of the Deep’).

Luckily, the fort at Red Sands lies off the main shipping channel and has undergone some restoration by the Project Redsand team. It is a timely intervention as without this the accelerating effect of corrosion may well have seen the end of the forts within a relatively short space of time. Mind you, if more money is not forthcoming this could still be their fate. I hope the plans include the restoration of the permanent walkways which used to link the towers (removed in the 1960s as a deterrent following the occupation of the forts by Radio Pirates).

Shivering Sands

After passing the last of the towers we pressed on to the second surviving fort at Shivering Sands, now reduced to just six towers after a 295 ton ship MV Ribersborg collided with one of the gun towers in thick fog in June 1963. Thankfully no-one was aboard at the time and the tower sank without loss of life (a crash at the Nore sea fort ten years earlier had more devastating consequences, resulting in the death of four maintenance workers). It is still possible to see a stump from one of the broken legs to this day.

The Waverley rounded Shivering Sands and gave us a distant view of Knock John (one of the navy forts) before taking us back to Gravesend. Although it was cold and grey we still had a marvellous outing and the Waverley is such a great ship to have sailed on – it is really quite astonishing to wander down to the engine room and watch the huge piston rods in action.